What is the different between Derive and Linked ?

[petrara]

I found fusion has two main ways to insert another fusion model in a design: either using the Derive command, or as Linked model. But from here the confusion starts: what is the difference between those two and when to use each?

[karina.harper]

Hi @petrara 

Here are some excerpts from this thread:

Insert design allows you to insert an instance into the current active component. Derive design (when you select components in the source and choose the "model objects" option) will create instances in the top-level of the target design only.

If you want to instance the entire source model in the target model and you don't want to modify a copy in the target, you should continue to use insert. 

Derive allows reuse of parts of the source when you don't want the whole thing and it also allows modification of those parts in the target.

There is also a bit more compute overhead to Derive when the source has changed, because that copy must be updated.

If you do multiple Inserts of the same design, they will be instances of one single design.  If you do Multiple Derives, they will not be associated with each other.

Let me know if that answers your question!

Karina

[petrara]

@karina.harper  thank you for the explanation, it helped a bit to understand some parts of the question, but it did not answer the most important part yet: when to use one and when to use another?

Let's say I want to insert another model in my design... when do you advise I should Insert Derive and when I should use drag-and-drop and have a Linked element in my model?

As you will be able to see in the attached image, I inserted two parts in my design. One by drag-and-drop and it has a chain link symbol by its name in the browser and the other one, by using "insert derive" and it has an arrow symbol by its name in the browser.
So far, I don't have a clear idea why we have this two options and what is the difference between them. More precisely: when (in what specific circumstances) I am supposed to use each of them? Could you please provide a practical example, explaining pros and cons for each procedure?

Thank you very much.

[jeff_strater]

Hi @petrara , hope you don't my me jumping in here.  There is no a clear-cut set of reasons for using one over the other, it really will depend on what you want to do with the referenced component.  As Karina said, the main difference is that Derive is a) a copy of the source, and b) can be less than the entire design.

So, some questions to ask are:

• Do I have lots of instances of this design in my design?  If so, use Linked designs, because those are way more efficient, in that they take up no room in your design.
• Do I want to use the entire referenced design as-is, or do I really want to get just one component from a larger design?  If so, use Derive, because you can selectively bring in just one sub-component from a larger design
• Do I need to make changes to the referenced design?  For example, if you bring in a component, and then need to drill a hole in it, that is going to be much easier if you use Derive.  You cannot modify a linked design in the context of the parent assembly (yet, we're working on that...), but because Derive is a copy, there is no problem doing that.  This also would allow you to simulate "Assembly features", where you make a change to just one instance of a component, leaving the others alone.

There are other differences, but I think this captures the gist of the main ones.  Hope it helps

[petrara]

@jeff_strater I don't mind at all, in fact your interventions are always welcome (and most important: they are extremely helpful!).
Thank you for the punctual explanation. This starts to make more sense for me now.

My observations so far:

DERIVE

- If I modify the SOURCE of a Derive, it will prompt me with an "Out of Date" message in the design where I imported the part and after updating, the modification will appear in the imported copy.

- The Derive DOES NOT come with any timeline history and any modification I make on it stays locally (does not propagate back to the original)

- I can Activate the Derived component

- Double-Click in timeline on the Derive will open it in a new tab and allow me to edit its features there (Including the timeline) 

LINK

- Drag and drop from the same project, will create a LINK.

- Drag and drop from different project will copy everything in my new design, but without creating a link.

- I CANNOT Activate the Linked component

- I CANNOT Edit/Modify the component

- I can Apply Constraints (Assemble) the Linked Component

- Breaking the Link will introduce the full timeline of the Linked Component and also allow me to Activate it and work locally on it as it's part of my model.

CONCLUSION:

Without knowing more about the real purpose of Link and Derive, I find those two features cluttering Fusion. One single feature would be enough with the possibility of Breaking the link.

So, if Fusion would have ONE feature that satisfies all requirements:

- insert the design (or part of it) as reference (hybrid reference, so one can make local modifications on it, if needed)

- be able to edit the original separately and have the alteration propagate in the derived design (where eventually could merge with the local alterations, eg. a hole that has been added locally)

- possibility to break the link between the derive and the original, and by doing that, the derive becomes purely local and it brings with it the original timeline.

Then it would make little sense to have Linked and Derive features. I understand this might bring a small drawback (the fact that you would have some sort of hybrid reference/linking) would make the design a bit bigger, but even in the current situation, linking doesn't work if adding from a different project, anyway (it creates a local copy).

Maybe the development team would be interested in reflecting over this aspect. Fewer and better optimized features (smarter) would make fusion a much more robust software, rather than having fuzzy features that are somewhat interchanging, but not always, except if it's Full Moon and only on Tuesday.

[garmitage]

In @petrara's last reply on this thread he stated that if you "Double-Click in timeline on the Derive will open it in a new tab and allow me to edit its features there (Including the timeline) ."  No such thing happens when I do that.  It just rolls back the design to whatever element I click on and displays a "Finish Base Feature" button.

What he wrote gave me the impression that it was essentially the same as breaking the link.  Is there a way to do that and make changes to the original geometry?

Thanks.

[TrippyLighting]

You don't have any linked components or derived entities (components, bodies, sketches, parameters)  in the screenshot you posted!

Derived entities have the little right-arrow symbol as part of their feature icon in the timeline and or browser.

There are a number of distinct differences between derived entities and linked componets.

Derive allows deriving parameters, sketches, and components from one design into another design while maintaining full parametric connectivity to the source design.

For example, a component might be developed in context and then derived into a new design to develop the CAA tool paths and associated set-ups. 

A linked compone on the other hand is a stand-alone design. It will maintain the parametric link to the source design. However, if a component is designed within the context of an assembly and then is to be re-used it will need to be exported with "save copy as" into the data panel, but then does not maintain the link to the source design.

The geometry of a derived component or body can be altered in the design I was derived in, allowing us to add features that are unique to that design they were derived into. A linked component can only be changed globally and all changes are then propagate to any of the designs the component was linked into.

[garmitage]

Hmmm.  Still a little confused.  Is it possible something else has to be present in a design before you bring a derived part in?  If you look at my timeline below, the first three icons are what showed up the first time I brought them in with derive, the next is a hole I put in one of the bodies, and the others are latter designs I brought in by linking or the derive command.  Any explaination for why the first one is different?

[garmitage]

Oh, I also see now that I misread @petrara's sentence and didn't realize it was opening the original part.  So is there a way to break the connection with the original and edit the original geometry?

[TrippyLighting]

  You might want to create a screencast of what actions you performed. The screenshot does not explain how the base features are created in the timeline.

[garmitage]

Well I don't know what I did on that original one, because on trying again it behaves as expected.  But I've got another question.  It was said that double-clicking open the source part so it can be edited, but my screencast below shows that I haven't been able to do that.  Can you clarify this?

 I'm getting an error uploading my screencast so I'm attaching a video.

 

[TrippyLighting]

I think you are misinterpreting what you see 😉

You ARE in fact in the source design and can make edits. The panel on the right is there to allow you to change the selection of stuff you want to derive.

So for example, if you've created another body in your source design or another sketch or parameter you also want to derive into the target design, you can change that in the panel.

[garmitage]

What you can't tell from the video is that when I try to right-click or double-click an element in the timeline of the original part after it opens, as one would do edit it, nothing happens.  And if I click either okay or cancel in the "Edit Derived Design" window, the part closes.  What am I missing?

[TrippyLighting]

Aha! Off to investigate. That'l be later though!

[jeff_strater]

I can maybe clear up some confusion here.  There are two actions that you can take on a Derived Feature (which lives in the "destination" design):  Open Source, and Edit Derive Feature:

Double-click takes you to Edit Derive Feature.  This UI allows you to only change what is derived.  You can select or de-select bodies, sketches, etc via this UI:

You are editing the Derive feature.  You are not editing the source design, which is why you cannot edit features in this UI.  If you want to edit the source, use Open Source.  This will create a new tab that will allow you to modify features in the source design.

[garmitage]

I hate inconsistent problems.  I was going to ask how you accessed that menu, but thought I'd go through the process again to see what happened.  Yesterday nothing happened if I right-clicked on a timeline icon (even closing, opening, and reconstructing the derived part multiple times), and today I get that menu.  Hard to troubleshoot with an inconsistent program operation, but thanks for getting me past it.